David Hughes is the Daily Telegraph's chief leader writer. He has been covering British politics for 30 years.

Boris Johnson owes Alastair Campbell

Full coverage of UK PoliticsI trust a bottle of the finest bubbly has arrived at Alastair Campbell's North London home from a grateful Boris Johnson. For the new Mayor of London owes Tony Blair's one-time spin doctor an enormous debt of gratitude.

Alastair Campbell's anti-BBC campaign has backfired with Boris

It was Campbell's remorseless hounding of the BBC – and more specifically its then defence correspondentÂ Andrew Gilligan -Â over the sexed up Iraq dossier allegations that has led, slowly but surely,Â to an old Etonian Tory (in chippy Alastair's book, the lowest of the low) running the nation's capital.

Gilligan lost his job after Lord Hutton's inquiry found that he and the BBC had been remiss in their reporting of Dr David Kelly's disquiet about the Downing Street dossier. The chairman and director general of the BBC went with him. It was the bleakest moment in the Corporation's recent history.

Campbell's decision to summon the world's press to a briefing simply to allow him to gloat about his "victory" over a great national institution still leaves a nasty taste.

So it is particularly satisfying that it has all backfired so spectacularly.Â While many predicted that Gilligan's career would never recover from the Hutton debacle, he has rebuilt his career as an investigative reporter for London's Evening Standard.

And in recent months Gilligan's meticulously researched revelations about the shenanigans in Mayor Livingstone's administration have played a crucial part in swinging London against Red Ken. Never has the cronyism that has characterized Livingstone's entire political career been so forensically exposed.

And it would not have happened if Campbell had not embarked on his anti-BBC crusade. You would need a heart of stone not to laugh.